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LNG World Shipping

LNGC owners have BWMS options

Fri 18 May 2018 by Paul Gunton

LNGC owners have BWMS options
Erma First worked with Golar LNG to optimise its system to the operator’s requirements (credit: Erma First)

Orders show clear priorities in choosing ballast water management systems

Judging by orders placed in the past few months for ballast water management systems (BWMS) on LNG carriers, a range of technologies are now considered suitable. Two orders in particular, however, suggest that US Coast Guard (USCG) type-approval is a significant factor in owners’ decision making, with the USA now an important destination for both import and export LNG cargoes.

In December, Greek ballast water management system maker Erma First secured a fleet-wide contract from Norway’s Golar LNG to supply its USCG type-approved ballest water treatment system (BWT) Fit. It uses filtration, electrolysis and electrochlorination as its treatment method and the compnay said in a statement that its equipment would be installed “on up to 16 LNG vessels”, which potentially covers the whole Golar fleet.

Fit for purpose

Fit was the first full-flow electrolysis system to receive USCG type-approval and the Golar order came just two months after it secured USCG type-approval. Installations are due to begin during the company’s next drydocking, scheduled for Q2 this year, and continue until the end of 2022, following Golar LNG’s drydocking schedule.

Erma First said it had worked intensively with the shipping company “over the previous months to optimise and adapt the system to the company’s vessels”. In the case of a previous contract that also benefited from cooperation with the customer, optimisation had involved specifying systems to suit each ship’s pumping, piping and other parameters, so that each installation could be completed within the ship’s normal drydocking.

In January, Alfa Laval of Sweden announced an order for its USCG type-approved UV-based BWMS from Nakilat, a Qatar-listed shipping and maritime company with the world’s largest LNG fleet. Few details were offered about when the order was placed or the vessels involved, but two PureBallast 3.1 systems of 2,000 m3/h will be retrofitted.

PureBallast 3.1 was selected for its small footprint, simple installation and its ease of use, head of Alfa Laval PureBallast Anders Lindmark said.

Oxygen stripping

Other systems that do not yet have USCG type-approval also claim to be well-suited for LNG carriers. US manufacturer NEI-Marine is working towards both USCG and IMO’s revised G8 type-approvals for its venturi oxygen stripping (VOS) BWMS.

This technology consists of an inert gas generator connected to the ballast line to strip the ballast water of all oxygen and kill the organisms in it. For LNG installations, a modification will allow it to use the LNG boil-off to power the installation.

Coldharbour Marine in the UK also uses inert gas as one component of its treatment system and the company’s chief executive Andrew Marshall told LNGWS that its target customer base is LNG carriers and tankers. Because of this, little training is needed to operate the system he said, because crews on those ship types are familiar with inert gas generators and the rest of its equipment “is super simple and requires little or no maintenance, so the time taken for the crew to achieve full competency on the system is very short”.

Doing away with ballest

Another option currently being developed for LNG carriers does not involve ballast treatment, or any ballast at all. French gas containment specialist Gaztransport & Technigaz (GTT), along with UK class society Lloyd’s Register (LR), China’s Dalian Shipbuilding Industry Corp and Belgian shipping company Exmar are developing  a ballast-free LNG carrier design.

In December, LR granted its ‘approval in principle’ to the design and in March the group began the next stage in its 30,000 m³ ‘B-Free’ initiative. Phase 2 of the project aims to develop the design further and validate results from the first phase by applying more detailed analysis and verification, including model testing. 

For mid-size LNG carriers such as this, ballast water is more critical to achieving sufficient draught for propeller immersion when the vessel is unladen than for stability. The B-Free design achieves this with a triangular-shaped lower part of the hull, allowing the vessel to sit deeper in the water when unladen, achieving the necessary propeller immersion for its 5.6 m diameter propeller while maintaining stability without needing ballast water.

The design is expected to have lower construction and operational costs than a conventional LNG carrier because there is no need for a BWMS.

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